Rivets and methods for their production and use

ABSTRACT

There is provided self piercing rivet comprising a substantially planar metal body portion ( 160 ) having deformable tabs (161) symmetrically disposed about a slit ( 162 ) as per the first embodiment. The upper portion of the body portion ( 160 ) is provided with a V-shaped recess ( 163 ) diverging from a point ( 164 ) adjacent the centreline of the body portion ( 160 ) and terminating at the upper edge ( 165 ) of the body portion ( 160 ). The V-shaped recess ( 163 ) divides the upper portion of the body portion ( 160 ) into head tabs ( 166 ) disposed to each side of the body portion ( 160 ). The upper remaining edges of the head tabs ( 166 ) enable the rivet to be partially driven and then set by deformation of the deformable tabs ( 161 ) and the head tabs ( 166 ) against respective sides of the riveted workpiece. Methods of producing the rivets and tools for their use are also provided.

[0001] This invention relates to a rivet and methods for theirproduction and use.

[0002] This invention has particular but not exclusive application to arivet for use in assembly of rolled-section metal framing for buildings,and methods for their production and use, and for illustrative purposesreference will be made to such application. However, it is to beunderstood that this invention could be used in other applications, suchas joining sheet metal elements generally.

[0003] In the construction of metal frame buildings, a significantproportion of the cost of the structure is the combination of the costof fixings and the labour to employ them. Metal framing remains in mostcases cost competitive with more traditional framing methods. However,it remains that the fixing costs associated with metal framing mean thatthe significant cost advantage held by metal framing stock over timberstock is not fully realised.

[0004] Metal framing presents particular fixing constraints. The fixingscannot remain too proud of the inner wall surface where cladding is tobe fixed, since this adds to the joint build height inherent where twosections of the same nominal dimensions are overlapped. The fixings mustsecure the respective elements in intimate contact, again to minimizebuild height at the join and to present as flat a mounting for claddingas possible. The fixings are advantageously employed in such a manner asto located the respective members rigidly.

[0005] There are many fixing methods currently employed in the industryto achieve these ends. The simplest method is the use of self-drillingor PK screws to join the elements. However, these are expensive in termsof unit cost, have a relatively high failure rate in terms of siftingproud of the surface, and are not particularly well adapted to provideclamping force between the elements. Blind rivets are also used.However, these require the predrilling of the elements to receive therivet, and are slow to install. Round rivets and PK screws are requiredin pairs to make a joint resistant to rotation about each fixing.

[0006] Australian patent 518231 describes a riveting system forconnecting thin sheet members together and comprising a hardened,waisted, self punching rivet and a complementary die set adapted topunch the rivet through and set the sheet material into the waistportion of the rivet. The disadvantages of this arrangement include theexpense of producing a high-tolerance, hardened rivet capable ofpunching a full diameter hole in both sheets, and the weight and cost ofa die set and tool capable of providing the requisite deformation forceabout the hole. In cases where the joint is to be secured againstrelative rotation, pairs of fixings are required, unless the joint isotherwise held spatially rigid.

[0007] Australian patent 577292 discloses a self piercing rivetingmachine comprising an automatic feed for top-hat section, round-headrivets and a ram and anvil driving and setting arrangement. In aconventional sense, the relatively hard rivet punches a full diameterhole through the members to be a riveted and is set against the anvil.Again, the rivets are expensive and the machine must generateconsiderable force to achieve the punch and set actions. In order torender the joint non-rotating, the rivets must be deployed in spacedpairs in the joint, unless the joint is otherwise held spatially rigid.

[0008] Australian patent application 11780/76 describes a sheet-joiningmachine whereby a punch and anvil are configured to punch and deform therespective sheet members so as to make a rivetless join. However, inpractice the size of the punched hole necessary to provide enoughmaterial in the join, coupled with hardening effects in the distortedmaterial, resulted in a large power requirement, raising the weight ofthe tool.

[0009] This invention in one aspect resides broadly in a rivetincluding:

[0010] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0011] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0012] a head portion formed or formable on the other said end.

[0013] The substantially elongate, uniform section of the body portionmay be substantially rectangular or other elongate prismatic section.Alternatively, the substantially elongate, uniform section may be acorrugated section or other like profile, whereby the form of the bodyprovides for stiffening against driving and setting loads applied. Thesubstantially elongate, uniform section may be selected to maximize theresistance to rotation of the rivet in a work piece. For example, thesection may be formed from a generally planar stock and having a ridgeor step formed therein.

[0014] The leading portion may be profiled in a like or different mannerto the body portion, if the body portion is profiled. However, it ispreferable that the leading portion be plane and unprofiled such thatthe leading portion is more readily deformable out of the plane. Theleading portion is preferably symmetrical about the bifurcation. Thebifurcation may extend to short of, at or into said body portion to formthe pair of deformable tabs. The deformable tabs are preferably disposedabout the bifurcation line in such a manner to permit the deformationthereof by a setting tool concurrently with the driving of the piercingportion through the pieces to be joined. The deformable tabs may beadapted to be set substantially in the plane of the body portion ortransversely of the plane of the body portion. The deformable tabs maybe deformed in the same direction or in substantially opposeddirections.

[0015] The bifurcation between the deformable tabs may comprise a slotor alternatively may comprise a frangible partition. In a yet furtheralternative, the bifurcation may be putative in that the combineddeformable tabs may be adapted to cooperate with bifurcation meansassociated with a driving or setting tool.

[0016] The formed or formable head portion may take any suitable formconsistent with the function of preventing the rivet from passingentirely through the workpiece. For example, the head portion maycomprise a peened portion of the end of the body portion, an otherwiseshaped section extending along the end and being of larger section thanthe elongate section of the body portion in at least one of its twodimensions, tabs extending from the end and formed substantiallyperpendicular to the body portion, tabs formed substantially in theplane of the body portion and deformable by setting in use, and tabsextending from the side edges of the body portion at the end thereof andforming a shoulder adapted to bear on the workpiece in use.

[0017] The rivet may be formed integrally or may be fabricated. Therivet will usually be of metal, although it is envisaged that someplastic apparatus may find use in temporary fixing roles. The bodyportion may be of any selected length, width and thickness determined bythe gauge and strength of the pieces to be joined. The extent of theformed or formable rivet head is selected having regard to the abilityof the joined material to resist pull-through of the rivet head, undersetting and service loads.

[0018] In the case of integral formation the rivet may be punched orotherwise cut from sheet material. For example, the rivet may besequentially punched from strip material. Where the rivet is punchedfrom strip material, the rivet may be punched or cut sequentially end toend along the centerline of the strip, side by side along one edge ofthe strip or alternating side by side along each edge of the strip.Preferably, the formed or formable head portions are formed from thestrip material prior to separation of the completed rivet from thestrip.

[0019] In a further aspect this invention resides broadly in a rivetincluding:

[0020] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0021] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0022] opposed lugs extending from each said side edge in the region ofthe other said end.

[0023] In a further aspect this invention resides broadly in a rivetincluding:

[0024] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0025] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0026] a formable head portion comprising a recess relieving theterminal edge of the other said end to form a deformable head lug eitherside of said recess.

[0027] The recess may be bounded by deformable head lugs which retain asubstantial portion of the terminal edge, such that the rivet may be atleast partially driven thereby, whereafter the head lugs may be deformedout of the plane of the body portion to form the rivet head. The recessmay be of any suitable shape. For example, the recess may be a squaresided recess, that is, a recess having side edges substantially parallelto the side edges of the body portion. Alternatively, the recess maycomprise a V-shaped recess converging toward the centreline of the bodyportion. The recess may comprise a cut-out portion, wherein the materialto be removed to form the recess is left with one or more points ofattachment in the manner of a chad. Preferably, the point of attachmentof the chad is such that the terminal edge of the chad may continue toserve as at least an initial driving portion for the rivet.

[0028] In a further aspect this invention resides in a method of forminga rivet including:

[0029] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0030] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0031] a head portion formed or formable on the other said end, fromstrip metal material and including the steps of:

[0032] sequentially forming a plurality of spaced partitionstransversely on said strip, said partitions serving as said bifurcationin the finished rivet;

[0033] sequentially punching said strip between said partitions to formone of said side edges and deformable tabs of each of adjacent rivets;and

[0034] sequentially shearing between said adjacent rivets to release thefinished rivet from the strip.

[0035] The formation of the respective partitions may be by any selectedmeans. For example, the partitions may be formed by shearing a slit orby punching a frangible partition into the strip. In the case of metalstrip, the partition may advantageously be formed by a first shear toform a slit, followed by one or more flattening steps adapted toreconfigure the strip for subsequent processing. The sequentiallypunching of the strip between formed partitions to form the side edgesand deformable tabs is preferably done in a single punching operation,although it is envisaged that this may be done in two or more punchingsteps.

[0036] In a further aspect this invention relates to a method of settinga self piercing rivet including:

[0037] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0038] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0039] a head portion formed or formable on the other said end, andincluding the steps of:

[0040] providing a fastening tool having driving means adapted to holdand drive said self piercing rivet piercing portion first towards asetting anvil opposed to said driving means;

[0041] locating a work piece having opposite surfaces between saiddriving means and setting anvil;

[0042] operating said driving means to drive said piercing portionthrough said work piece until said head portion is abutting one saidopposite surface, said anvil being selected to progressively deform saiddeformable tabs into engagement with the other said opposite surface.

[0043] In a further aspect this invention relates to a fastening toolfor a self piercing a rivet including:

[0044] a body portion having respective ends and being of substantiallyelongate, uniform section between said ends;

[0045] a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and

[0046] a head portion formed or formable on the other said end, andincluding;

[0047] driving means adapted to hold and drive said self piercing rivetthrough a workpiece to be joined until said head portion is abutting onesaid workpiece;

[0048] a setting anvil opposed to said driving means and adapted to setsaid deformable tabs against said workpiece;

[0049] magazine means adapted to store a plurality of said self piercingrivets; and

[0050] feed means adapted to sequentially supply said self piercingrivets from said magazine means to said driving means between drivingoperations thereof.

[0051] Preferably, the anvil means is selected to deform the deformabletabs out of the plane of the body portion and in opposed directions toachieve the set. The driving means may be a manually operated mechanicalor hydraulic driving means. Alternatively, the driving means may be of apowered type, such as electromechanical, hydraulic or pneumatic means.

[0052] The magazine means may be adapted to store the plurality of selfpiercing rivets in any selected orientation determined by the feedmeans. However, in the case of the sequentially punched rivets, theseare advantageously magazined with their planar faces abutting, in orderto present the maximum linear density and thus shorten the magazine. Tothis end, the rivets are preferably adhered together by means permittingthe feed means to shear a rivet from the row in the magazine asrequired.

[0053] In a hand tool for driving the fastening means there may beprovided a tool body having a fixed jaw and a movable jaw mountedthereto. The movable jaw may for example be mounted in sliding relationto the tool body in a bore or on a track or the like. Alternatively, themovable jaw may be hinged to the fixed jaw. The movable jaw may beadapted to clamp a workpiece between the jaws. For example, the toolbody and the movable jaw may be provided with camming means, lever,speed clamp or other threaded means to effect clamping. The movable jawmay be provided with a setting anvil in the form of an anvil piece orthe setting anvil may be integrally formed in a hardened jaw.

[0054] The driving means may comprise a plunger or ram extending throughthe tool body toward the setting die. For example, the tool body may beprovided with a bore or slot in which the plunger or ram may be mountedwhereby the leading end may be advanced toward the setting anvil.Preferably the plunger or ram is provided with a profiled leading end toconform to the driving edge of the rivet, and to this end it is alsopreferred that the bore in the tool body be profiled at its jaw end toconform to the leading end. The magazine is preferably configured tointerpose the rivet close to the jaw end of the profiled leading end.

[0055] The plunger or ram may be operable by any suitable manual orpowered means as hereinbefore described and including by means of simpleor compound levers, lost motion arrangements, hydraulic ram or the like.

[0056] In order that this invention may be more readily understood andput into practical effect, reference will now be made to theaccompanying drawings which illustrate preferred embodiments of theinvention and wherein:

[0057]FIG. 1 is a view of a rivet in accordance with the presentinvention;

[0058]FIG. 2 is a view of an alternative rivet in accordance with thepresent invention;

[0059]FIG. 3 is a bottom plan view of the apparatus of FIG. 2 in use;

[0060]FIG. 4 is a vertical section through a joint made using theapparatus of FIG. 2;

[0061]FIG. 5 is an end view of a joint made utitlizing the apparatus ofFIG. 2;

[0062]FIG. 6 is a bottom plan view of a joint made using the apparatusof FIG. 1;

[0063]FIG. 7 is a vertical section through a joint made using theapparatus of FIG. 1;

[0064]FIG. 8 is an end view of a joint made utitlizing the apparatus ofFIG. 1;

[0065]FIG. 9 is a top plan view of the apparatus of FIG. 1 in use;

[0066]FIG. 10 is a setting anvil suitable for use in a tool for settingthe apparatus of FIGS. 1 and 2;

[0067]FIG. 11 is a side view of a tool for use with the apparatus ofFIG. 1 operably closed about a workpiece;

[0068]FIG. 12 is a partial side view of the tool of FIG. 11, operativelyopen to receive a workpiece;

[0069]FIG. 13 is a partial front view of the tool of FIG. 11;

[0070]FIG. 14 is an exploded perspective view of the tool of FIG. 11;.

[0071]FIG. 15 is a view of an alternative rivet in accordance with thepresent invention;

[0072]FIG. 16 is a perspective view of the rivet of FIG. 15;

[0073]FIG. 17 is a plan view of the rivet of FIG. 15;

[0074]FIG. 18 is a further alternative rivet in accordance with thepresent invention;

[0075]FIG. 19 is a view of the apparatus of FIG. 18 in use;

[0076]FIG. 20 is a section through a joint formed using the apparatus ofFIG. 18;

[0077]FIG. 21 is an alternate section through the joint made with theapparatus of FIG. 18;

[0078]FIG. 22 is an end view of the joint made using the apparatus ofFIG. 18;

[0079]FIG. 23 is a view of the apparatus of FIG. 18 showing fold linepositions;

[0080] FIGS. 24-27 are a progressive series of views illustrating themaking of a joint using apparatus in accordance with the presentinvention using apparatus for the purpose;

[0081]FIG. 28 is a perspective view of a tool for setting rivets inaccordance with the present invention;

[0082]FIG. 29 is an exploded view of the tool of FIG. 28

[0083]FIG. 30 is a yet further alternative rivet in accordance with thepresent invention;

[0084] FIGS. 31 to 34 illustrate the rivet of FIG. 30 in use;

[0085]FIG. 35 is a driving element for the tool of FIG. 28 for use withthe rivets of FIGS. 18 and 30, and

[0086] FIGS. 36 to 38 illustrate the driving element of FIG. 35 in use.

[0087] With reference to FIGS. 1 and 2 there are illustrated alternateembodiments of rivets in accordance with the present invention. In theembodiment of FIG. 1 there is provided a rivet 10 of unitaryconstruction and comprising a substantially planar body portion 11having a pair of opposed lug portions 12 extending coplanar of the bodyportion 11 about an end 13 thereof. Pair of deformable tabs 14 isintegral and coplanar with the body portion 11 and are disposed about aslit 15. The outer ends 16 of the edge portions 14 are relieved from theside edges 17 of the body portion 11 to form a piercing point 20. Thelugs 12 are formed coplanar with a pair of locking tabs 21 extendingbeyond the end edge 13 of the body portion 11.

[0088] The use of the rivet 10 of FIG. 1 is best illustrated in FIGS. 6,7, 8 and 9 which illustrate the rivet 10 when used to fix overlappingsheet members 22 and 23. The rivet is supported to be driven by drivingmeans (not shown) of two-stage type. The first stage bears against theend 13 and drives the point 20, deformable tabs 14 and body member 11through the sheet materials 22, 23 against the reaction of the anvil 24illustrated in FIG. 10. The first stage drives the rivet through untilthe lugs 12 bear on the outermost 22 sheet material. The second stage ofthe driving means then serves to bend the tabs 21 down to contact theoutermost 22 of the sheet materials. As the point 20 penetrates thelower 23 sheet, the forming joint is supported on lands 25 of the anvil24. The lands 25 meet at an apex 26 adapted to coincide with the point20 of the advancing rivet 20. Respective forming surfaces 27 of theanvil 24 pick up respective deformable tabs 14 and with the advancingrivet 10 deform the deformable tabs 14 until the lower sheet 23 iscontacted at 30, thus placing the joint in compression between thedeformable tabs 14 and the lugs 12. The tabs 21 provide resistance topull through of the rivet 10.

[0089] In the alternative embodiment of FIG. 2, there is provided arivet 31 of substantially the same form as that illustrated I FIG. 1,with like features to be interpreted as per FIG. 1. The sole differencebetween the two embodiments is the absence of the tabs 21, thus removingthe requirement for use of a two stage driving means.

[0090] In both embodiments, the apparatus was produced from 304stainless strip of 1.2-mm thickness by a multiple stage punchingprocess. In the embodiment of FIG. 1 the stainless strip advances to ashearing station wherein a shear cuts the slits 15 of respective rivets10 transverse to the long edge of the strip and spaced apart by thepitch of the rivet 10. Following the shearing of the strip to form theslits 15, the distorted strip is passed through two flattening stages tobring the strip back into planarity. Thereafter, the strip passesthrough respective punches to punch out the spaces bounded by the lugs21 and the end 13 by means of a first punch, and the space bounded bythe deformable tabs 14 and lugs 12 of adjacent rivets 10 by a secondpunching operation. After sequential punching of the respective spaces,the strip passes to a shearing station where the rivet 10 is cut fromthe advancing strip by shearing between the respective tab 21 and lug 12portions, along edges 32.

[0091] With reference to the apparatus of FIG. 2, this is produced insubstantially the same manner as the apparatus of FIG. 1, except thatthe absence of tabs 21 means that the first punching step may bedispensed with, the rivet 31 being separated in the final shearing stepat adjacent lug portions through sheer line 33.

[0092] In FIGS. 11 to 14 there is illustrated a hand tool for use withthe rivet 10 and including a machined tool body 40 having a smoothlongitudinal bore 41 therethrough. Mounted at the forward end of thetool body 40 is a magazine and inner jaw assembly 42 that is secured tothe tool body 40 at mounting face 43 by bolts 44. The magazine and innerjaw assembly 42 has a spigot 45 adapted to enter and conform closelywith the bore 41, to in effect provide a stepped bore within the toolbody 40. A magazine portion 46 is adapted to receive a flats-togetherstack of the rivet 10, with their piercing points facing forward. Themagazine and inner jaw assembly 42 has a front face 47 adapted to bearagainst the workpiece 50. The front face 47 has a fastening deliveryslot 51 which extends through the magazine and inner jaw assembly 42 tointersect and form the upper stop of the magazine space, and extendsrearward to coaxially enter the bore of the spigot 45. The magazineportion 46 is loaded from beneath and is closed by an end cap and spring(not shown) that cooperate to urge the stack of rivets up such that theuppermost fastening is aligned with the delivery slot 51.

[0093] An outer movable jaw assembly 52 includes a jaw portion 53 havingsecured at its outer end the anvil 24 illustrated in FIG. 10. The jawportion 53 is located in sliding relation to the tool body 40 byinteraction of a shank 54 with a bore 55 provided in the tool body 40.The bore 55 is intersected by a cutout 56 whereby the shank may receivetherein a spring 57 and spring stop 60 secured by roll pin 61 whenassembled to the tool body 40. Extending coaxially from the rear of theshank 54 is an integral operating rod 62 adapted to pass through a bore63 provided in a reaction lug 64 defining the rear wall of the cutout56. A lever cam 65 is pivotally secured to the end of the operating rod62 in assembly by pin 66, cam thrust on the reaction lug 64 beingtransmitted through hardened thrust washer 67. Operation of the cam 65against the bias of spring 57 draws the jaw portion toward the workpiece50 to clamp the workpiece 50 against the anvil 24.

[0094] At the rear of the tool body 40 there is provided a pair ofvertical slots 70 above and below the bore 41, the slots 70 beingintersected by cross drillings 71. The slots 70 receive respective lostmotion links 72 that are pivotally retained therein by pins 73. A pairof handles 78 are pivotally interconnected at 74 with a ram 75 gauged topass in to the bore 41. The forward end of the ram 75 is secured to ahardened driving pin 76 having a flat section 77 profiled to passthrough the section of the slot 51 to drive the fixing therethrough.Mechanical advantage is provided by virtue of the links 72 having theirouter ends pivotally connected to the respective handles 78 at 80, beinga short distance from the pivot 74 relative to the handle length.

[0095] With reference to the alternative embodiments of rivetsillustrated in FIGS. 15-23 and setting apparatus for use with rivets inaccordance with the present invention and illustrated in FIGS. 24-29,the applicant provides as follows:

[0096] FIGS. 15-17 illustrate the rivet illustrated generally at 90formed substantially as per the previous examples. This embodiment isdistinguished by being punched having an opposite portion 91 extendingsubstantially co-axially to the rivet 90. The offset 91 fulfills severalfunctions, the first function is to substantially stiffen the rivet 90,which stiffening is more pronounced in the body 92 and between the lugs93 as opposed to the deformable tabs disposed about the slit 95. Thesecond advantage of the opposite 91 is that the lugs 93 are out ofalignment when set into the workpiece thus interrupting the lines ofstress imposed on the workpiece.

[0097] With reference to the further rivet illustrated in FIGS. 18-23,these comprise a substantially planar body portion 100 having deformabletabs 101 symmetrically disposed about a slit 102 as per the firstembodiment. However in this embodiment the upper portion of the body isprovided with a pair of divergent slits 103 extending from pointsadjacent the centreline of the body 100 and terminating at the upperedge of the body 100. The slits 103 divide the upper portion of the body100 into tabs 104 disposed to each side of the body portion 100 and adrivable knockout 105 between the slits 103.

[0098] The distinguishing feature of the apparatus of FIGS. 18-23 isthat the need for lugs extending generally beyond the sides of the bodyportion 100 is dispensed with. However since the upper remaining edgesof the tabs 104 are of relatively small size, the drivable knockout 105remains in place while the rivet is driven and set as illustrated inFIGS. 19-23. Referring to FIG. 19 it can be seen that the workpiece 107has had the apparatus of FIG. 18 driven therethrough and set with therespective tabs 104 formed against the workpiece 107 by bending out ofthe plane of the body 100 in respective directions. The setting actionconcurrently sets the deformable tabs 101 on the reverse side of theworkpiece 107 as illustrated in FIG. 22. The forming lines 108, 110 areillustrated in FIG. 23. In the setting process, the metal of the body100 in the region of the apex of the slits 103 work hardens tofrangibility and breaks off to form a metal chad 111.

[0099] With reference to the alternative fastening tool illustrated inFIGS. 24-29 and referring first to the sequential drawings of FIGS.24-27, there is provided a tool having a static body portion 120 havinga movable clamping jaw 121 pivoted thereto about pinned 122. Theclamping jaw 121 is provided with a setting anvil portion 123 which isbounded by clamping faces 124. The clamping faces 124 opposecorresponding clamping faces 125 provided on the static body 120. Aworkpiece 126 is clamped between the respective clamping surfaces 124and 125 by an operating rod 127 pivoted to the movable jaw 121 at pivot130. The static body 120 is provided with a driving assembly bore 131intersected by a magazine bore 132. Slidably mounted in the bore 131 isa driving member 133 driven forward by the action between fixed handle134 and moving handle 135 having a primary pivot at 136 and gainingsecondary mechanical advantage via link 137 pivoted to the movablehandle end at 140 and to the driving member 133 at pivot 141.

[0100] Magazined rivets 142 pass through the magazine bore 132 and arein sequential index with the driving member 133.

[0101] In use the workpiece 126 is inserted between the clampingsurfaces 124, 125 whereupon the operating rod 127 is operated to closethe clamping surfaces 124, 125 against the workpiece 126. Operation ofthe movable handle relative to the fixed handle 134 effects the forwardmotion of the driving motion 133 against the indexed rivet andthereafter drives the rivet through the workpiece 126 to be set againstthe setting anvil portion 123 of the movable jaw 121.

[0102] With reference to the full perspective view and exploded view ofthe aforementioned tool illustrated in FIGS. 28 and 29 respectively, thecomponents described are numbered according to FIGS. 24-27.

[0103] It can be seen that the operating rod 127 is operated by anovercentering mechanism 145 comprising a hand lever 146 pivoted to thefixed handle 134 at 147 and itself being pivoted in an overcenteringposition at 150 to the operating rod 127, which is duplicated on eachside of the fixed handle 134 to provide symmetrical loading.

[0104] With reference to operation of the driving member 133, the link137 is paired on either side of the static body 120. The movable handle135 has yoke arms 151 extending each side of the tool and pivotedthereto by pivot pin 136. The ends of the links 137 are pivoted to theyoke arms 151 at 140.

[0105] With reference to the alternate rivet of FIG. 30, there isprovided a substantially planar body portion 160 having deformable tabs161 symmetrically disposed about a slit 162 as per the first embodiment.However in this embodiment the upper portion of the body is providedwith a V-shaped recess 163 diverging from a point 164 adjacent thecentreline of the body 160 and terminating at the upper edge 165 of thebody 160. The V-shaped recess 163 divides the upper portion of the body160 into head tabs 166 disposed to each side of the body portion 160.

[0106] The distinguishing feature of the apparatus of FIG. 30 is thatthe need for lugs extending generally beyond the sides of the bodyportion 160 is dispensed with. The upper remaining edges of the tabs 166enable the rivet to be partially driven and set as illustrated in FIGS.31-34. The tool for setting rivets such as those illustrated in FIGS. 18and 30 are modified as illustrated in FIGS. 35 to 38, wherein there isprovided as fixed tool body 170 and a movable jaw 171 having a settinganvil 172 as before. The driving member (not shown) has pivoted to itsouter end a pair of adjacent driving elements 173 via hinge elements174. The driving elements 173 each have a cam 175 on a face thereof, andthe drive slot 176 of the fixed tool body 170 is relieved to take thecam in sliding relation at grooves 177. The relieved grooves 177terminate at respective camming surfaces 180 which the cams 175 mayengage. The drive slot 176 is tapered to allow the cam 175 to deflectits respective driving element 173. The workpiece end of the slot 176 isrelieved at 181 to allow the head tabs 166 room to be folded over.

[0107] It will of course be realised that while the foregoing has beengiven by way of illustrative example of this invention, all such andother modifications and variations thereto as would be apparent topersons skilled in the art are deemed to fall within the broad scope andambit of this invention as defined in the claims appended hereto.

1. A rivet including: a body portion having respective ends and being ofsubstantially elongate, uniform section between said ends; a leadingportion extending from one said end substantially coplanar with saidbody portion and tapering from respective side edges thereof to form apoint, said leading portion being bifurcated from said point toward saidbody portion to form a pair of deformable tabs; and a head portionformed or formable on the other said end.
 2. A rivet according to claim1, wherein said substantially elongate, uniform section of the bodyportion is substantially rectangular in section.
 3. A rivet according toclaim 1 or claim 2, wherein said leading portion is substantiallysymmetrical about said bifurcation.
 4. A rivet according to any one ofthe preceding claims, wherein said deformable tabs are adapted to bedeformed in a direction substantially transverse of the plane of thebody portion.
 5. A rivet according to claim 4, wherein said deformabletabs are adapted to be deformed in substantially opposed directions. 6.A rivet according to any one of the preceding claims, wherein saidbifurcation between the deformable tabs comprises a slot.
 7. A rivetaccording to any one of the preceding claims, wherein said formed orformable head portion is selected from a peened portion of the end ofthe body portion, an otherwise shaped section extending along the endand being of larger section than the elongate section of the bodyportion in at least one of its two dimensions, tabs extending from theend and formed substantially perpendicular to the body portion, tabsformed substantially in the plane of the body portion and deformable bysetting in use, and tabs extending from the side edges of the bodyportion at the end thereof and forming a shoulder adapted to bear on theworkpiece in use.
 8. A rivet including: a body portion having respectiveends and being of substantially elongate, uniform section between saidends; a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; andopposed lugs extending from each said side edge in the region of theother said end.
 9. A rivet including: a body portion having respectiveends and being of substantially elongate, uniform section between saidends; a leading portion extending from one said end substantiallycoplanar with said body portion and tapering from respective side edgesthereof to form a point, said leading portion being bifurcated from saidpoint toward said body portion to form a pair of deformable tabs; and aformable head portion comprising a recess relieving the terminal edge ofthe other said end to form a deformable head lug either side of saidrecess.
 10. A rivet according to claim 9, wherein said recess is boundedby deformable head lugs which retain a substantial portion of theterminal edge, such that the rivet may be at least partially driventhereby, whereafter the head lugs may be deformed out of the plane ofthe body portion to form the rivet head.
 11. A rivet according to anyone of claims 9 and 10, wherein said recess is selected from a squaresided recess, a V-shaped recess converging toward the centreline of thebody portion, and a recess comprising a cut-out portion wherein the chadis left with one or more points of attachment.
 12. A rivet according toclaim 11, wherein said point of attachment of the chad is such that theterminal edge of the chad may continue to serve as at least an initialdriving portion for the rivet.
 13. A rivet according to claim 11,wherein said recess is a V-shaped recess.
 14. A method of forming arivet including: a body portion having respective ends and being ofsubstantially elongate, uniform section between said ends; a leadingportion extending from one said end substantially coplanar with saidbody portion and tapering from respective side edges thereof to form apoint, said leading portion being bifurcated from said point toward saidbody portion to form a pair of deformable tabs; and a head portionformed or formable on the other said end, from strip metal material andincluding the steps of: sequentially forming a plurality of spacedpartitions transversely on said strip, said partitions serving as saidbifurcation in the finished rivet; sequentially punching said stripbetween said partitions to form one of said side edges and deformabletabs of each of adjacent rivets; and sequentially shearing between saidadjacent rivets to release the finished rivet from the strip.
 15. Amethod according to claim 14, wherein said partitions are formed byshearing a slit.
 16. A method according to claim 15, wherein said slitis formed by a first shear step to form a slit, followed by one or moreflattening steps adapted to reconfigure the strip for subsequentprocessing.
 17. A method of setting a self piercing rivet including: abody portion having respective ends and being of substantially elongate,uniform section between said ends; a leading portion extending from onesaid end substantially coplanar with said body portion and tapering fromrespective side edges thereof to form a point, said leading portionbeing bifurcated from said point toward said body portion to form a pairof deformable tabs; and a head portion formed or formable on the othersaid end, and including the steps of: providing a fastening tool havingdriving means adapted to hold and drive said self piercing rivetpiercing portion first towards a setting anvil opposed to said drivingmeans; locating a work piece having opposite surfaces between saiddriving means and setting anvil; operating said driving means to drivesaid piercing portion through said work piece until said head portion isabutting one said opposite surface, said anvil being selected toprogressively deform said deformable tabs into engagement with the othersaid opposite surface.
 18. A fastening tool for a self piercing a rivetincluding: a body portion having respective ends and being ofsubstantially elongate, uniform section between said ends; a leadingportion extending from one said end substantially coplanar with saidbody portion and tapering from respective side edges thereof to form apoint, said leading portion being bifurcated from said point toward saidbody portion to form a pair of deformable tabs; and a head portionformed or formable on the other said end, and including; driving meansadapted to hold and drive said self piercing rivet through a workpieceto be joined until said head portion is abutting one said workpiece; asetting anvil opposed to said driving means and adapted to set saiddeformable tabs against said workpiece; magazine means adapted to storea plurality of said self piercing rivets; and feed means adapted tosequentially supply said self piercing rivets from said magazine meansto said driving means between driving operations thereof.
 19. Afastening tool according to claim 18, wherein said anvil means isselected to deform the deformable tabs out of the plane of the bodyportion and in opposed directions to achieve the set.
 20. A fasteningtool according to claim 18 or claim 19, wherein said magazine means isadapted to magazine said plurality of rivets with their planar facesabutting.
 21. A fastening tool according to any one of claims 18 to 20,wherein said anvil means comprises a movable jaw adapted to clamp aworkpiece to a tool body associated with said driving means.
 22. Afastening tool according to claim 21, wherein said anvil means is ananvil piece I assembly with said movable jaw.
 23. A fastening toolaccording to any one of claims 18 to 22, wherein said driving meanscomprises a plunger or ram provided with a profiled leading end toconform to the driving edge of the rivet, and wherein a bore is providedin the tool body that is profiled at its jaw end to substantiallyconform to said leading end.